Difference between revisions of "Part:BBa K1632010:Design"

Revision as of 23:21, 18 September 2015

fimB (wild-type)

Design Notes

sequence confirmed

Materials and Methods

Construction

All the samples were DH5alpha strain with antibiotic resistance to ampicillin and kanamycin.

(1) PBAD/araC_fimB(wild-type) (pSB6A1) + fim switch[default ON](wild-type)_rbs_gfp (pSB3K3)
(2) PBAD/araC_fimB(wild-type) (pSB6A1) + fim switch[default OFF](wild-type)_rbs_gfp (pSB3K3)
(3) pSB6A1 + fim switch[default ON](wild-type)_rbs_gfp (pSB3K3) …positive control 1
(4) pSB6A1 + fim switch[default OFF](wild-type)_rbs_gfp (pSB3K3) …negative control 1
(5) PBAD/araC_fimB(wild-type) (pSB6A1) + J23119_rbs_gfp(pSB3K3) …positive control 2
(6) PBAD/araC_fimB(wild-type) (pSB6A1) + rbs_gfp(pSB3K3) …negative control 2

Fig. 1. Plasmids

Assay protocol

1. Prepare overnight cultures for each sample in 3 mL of LB medium containing ampicillin (50 microg / mL), kanamycin (30 microg / mL)　and glucose (final concentration is 0.5 %) at 37 ℃ for 12h.
2. Make a 1:100 dilution in 3 mL of fresh LB containing Amp, Kan and glucose (final concentration is 0.5 %).
3. Incubate the cells at 37 ℃, shaking at 180 rpm until the observed OD590 reaches 0.4 (Fresh Culture).
4. After the incubation, take 1 mL of the samples, and centrifuge at 5000x g, 1 min, 25 ℃
5. Remove the supernatant.
6. Suspend the pellet in 1 mL of LB containing Amp and Kan, and centrifuge at 5000x g, 1 min, 25 ℃
7. Remove the supernatant.
8. Suspend the pellet in 1 mL of LB containing Amp and Kan, and centrifuge at 5000x g, 1 min, 25 ℃
9. Remove the supernatant.
10. Suspend the pellet in 1 mL of LB containing Amp and Kan.
11. Add 30 microL of suspension in the following medium.
① 3 mL of LB containing Amp, Kan, glucose (final concentration is 0.5 %) and 30 microL of sterile water
② 3 mL of LB containing Amp, Kan and 30 microL of 2 mM　arabinose (final concentration of arabinose is 20 microM)
③ 3 mL of LB containing Amp, Kan and 30 microL of 20 mM arabinose (final concentration of arabinose is 200 microM)
④ 3 mL of LB containing Amp, Kan and 30 microL of 500 mM arabinose (final concentration of arabinose is 5 mM)
※ As for C and D, the suspension were added only in medium ① and ④.
12. Incubate the samples at 37 ℃, shaking at 180 rpm for 6.5 hours. (Measure OD590 of all the samples every hour.)
13. After the incubation, take the samples, and centrifuge at 9000x g, 1min, 4℃.
14. Remove the supernatant.
15. Add 1 mL of filtered PBS (phosphate-buffered saline) and suspend. (The ideal of OD is 0.3)
16. Dispense all of each suspension into a disposable tube through a cell strainer.
17. Use flow cytometer to measure the fluorescence of GFP. (We used BD FACSCaliburTM Flow Cytometer of Becton, Dickenson and Company.)

Result

Fig. 1. The histograms of the samples measured by flow cytometer

Fig. 2. Determination of percemtage of [ON] state and colony formation using plasmid mixture extracted cell expressing FimB.

Fig. 3. DNA sequencing results of fim switch(wild-type)

Source

PCR from MG1655

References

Timothy S. Ham et al. (2006) A Tightly Regulated Inducible Expression System Utilizing the fim Inversion Recombination Switch. Biotechnol Bioeng 94(1):1-4
Hung M. et al. (2014) Modulating the frequency and bias of stochastic switching to control phenotypic variation. Nat Commun 5:4574. doi:10.1038/ncomms5574